Body weight (BW) is an important physiologic parameters in pediatric medicine given it's an essential factor for determining optimal drug dosages and intravenous fluid requirement, DC shock energy voltage needed for cardiorespiratory arrest, and correct equipment sizes in pediatric patients undergoing resuscitation. For example, many medications for children, including life-saving medications, are dosed on a per weight basis (e.g., mL/kg). Emergency situations, however, may preclude the ability to weigh a child on a scale. In addition, the availability of accurate weight scales is limited in many locations in the developing world. There is a need for methods, systems, and apparatus to accurately and efficiently predict BW without the use of a scale.